The present invention pertains to a safety stop block designed for use on a fixed stroke power press preventing inadvertent downward movement of the ram of the press while performing maintenance or die tool replacement.
The use of safety blocks on power presses is well known in the prior art and their use is mandated by state and federal laws. Given the tremendous forces generated by these presses, inadvertent downward movement of their rams while maintenance or die tool replacement is being performed can cause severe damage to an operator's hand or limbs as well as to the press.
Known prior art safety blocks include U.S. Pat. No. 3,855,921 and U.S. Pat No. 3,855,920. These patents attempted to solve the problem of needing numerous safety blocks of varying heights to accommodate varying shut heights presented by different die sets used on the respective press. The above referenced patents disclose an adjustable stop block. Operation of these stop blocks is time consuming having to adjust the height with each different shut height. Also, a large shut height necessitating using a large sized safety block is cumbersome to operate. The standard lengths of these safety blocks generally vary between 12 to 24 inches.
Also known in the prior art is the jack-type adjustable safety block shown in U.S. Pat. No. 2,653,560. Again, it is time consuming to adjust the safety block with each different shut height. Another limitation of these safety blocks is that they are positioned on the bolster plate or press bed and beneath the upper die shoe. A problem arises when the die tool encompasses the entire die ram area leaving no space to position the safety block. As a result of these limitations use of safety stop blocks are neglected as profitability is the main concern. Present commercial safety stop blocks, available from Rockford Systems, Inc. include an aluminum safety block with wedge attachments for adjustments in shut heights and an adjustable screw device block, have not resolved all the above defined limitations.